Pneumatic sheet separator



NOV- 24, 1964 R. R. TARBUCK 3,158,367

PNEUMATIC SHEET SEPARATOR Filed OO'C. 23, 1959 Fig. 2

o l2 F134 -g INVENTOR.

ATTORNEY United States Patent O 3,158,367 PNEUMATIC SHEET SEPARATOR Robert R. Tarbuclr, West Chester, Pa., assignor to Burroughs Corporation, Detroit, Mich., a corporation of Michigan Filed Oct. 23, 1959, Ser. No. 848,441 7 Claims. (Cl. 271--26) This invention relates generally to sheet feeding systems and more particularly to improvements in devices for separating sheets individually and successively from a stack of sheets.

Presently known devices for separating a sheet from the top or end of a stack have applied air to the sheet by means of suction or vacuum heads. These devices have been open to certain objections. First, the high vacuum employed tends to separate additional sheets in excess of the topmost one where the sheet material is semi-porous or pervious to air. Also, when separating sheets from the top of a stack of mixed sheets of various sizes, where the stack has not been jogged or previously edge-aligned, it is necessary to limit the position of the vacuum head to the least common area of the various sheets in the stack. In such case, certain areas of the separated sheets will not be supported by the vacuum head but will hang down lirnply thus making delivery of the separated sheets to associated forwarding devices more diiiicult.

The principal object of the present invention is tov provide a sheet separating device of improved design which will avoid the above-mentioned ditiiculties.

Another object of the invention is to provide a pneumatic device for separating sheets one at a time in succession from the top or end of a stack of sheets.

A further object of the invention is to provide such a device which may be operated selectively either by vacuum or positive air pressure.

These and other objectives wil-l be more fully revealed in the following detailed description of a specific embodiment of the invention when read in conjunction with the accompanying drawings in which:

FIG. 1 is one form of sheet feeding apparatus embodying the invention;

FIG. 2 is a view taken in the direction of arrows 2 2 of FIG. 1;

FIGS. 3 and 4 show progressive stages of a sheet being separated from the top of a stack;

FIG. 5 shows the sheet completely separated from the stack; and

FIG. 6 illustrates one method of stripping the sheet from the separating device` Considered briefly in its broad aspects, the invention comprises a sheet separating head through which a stream of air is passed at high velocity to create a low pressure area above the top sheet of a stack adjacent to one end of the sheet. This causes the end portion of the sheet to rise toward the head whereby the low pressure area gradually extends toward the opposite end of the `sheet to eiiect a progressive separation or peeling of the sheet from the top of the stack.

Referring to the drawings, the invention comprises an elongated body or head 10 constructed in the form o an air foil and preferably of rectangular cross-section and having an end portion 12 disposed at an acute angle with the top of a stack ot sheets S, the stack being supported on an elevating table 14 between fixed end guides 16 and 18. The bottom surfaces 2t) and 22 of head 1i) are formed iiat and provided with a groove 24 which terminates in an enlarged portion 26. A yhose 28 secured to head 10, at an acute angle to the bottom surface 22, communicates with the enlarged portion 26 for applying optionally either vacuum or positive air pressure to the ice top of the stack S from a suitable source such as a reversible pump P.

The operation will be described with respect to the use of vacuum, however, it will become apparent hereinater that the use of positive air pressure will eiect a separation of the sheets from the stack equally as etiicien as the use of vacuum.

In operation, vacuum is applied through hose 28 from the source P. The air moves at high velocity thus creating a low pressure area in the enlarged portion 26 and in the immediate vicinity thereof above the top of stack S causing the leftward portion of the top sheet S to rise 'and adhere to head 1i), as seen in FIG. 3, by reason of the atmospheric pressure below the top sheet. As the sheet S thus covers or seals the enlarged portion 26, the low pressure area on the top of sheet S expands along groove 24 toward the right causing additional portions of the sheet to separate or peel progressively from the stack and similarly adhere to head 10 as shown in FIG. 4. Sheet S then bends around the heel 30 at the intersection of surfaces 20 and 22 and the action progresses until the entire top sheet has been separated from the stack and is now held to head 10 as seen in FIG. 5. The bend at heel 30 causes any additional sheets which may have adhered to the top sheet S to separate from the top sheet and drop back to the stack S.

The separated sheet S may be stripped from head 10 in any well known manner, however, by way of example, head 10 is illustrated as being movably mounted for conveying the separated sheet S to forwarding rollers 32 and 34 for delivery to its destination. For such purpose, head 10 may forni part of a carriage means and may be secured to a vertical supporting member 36 thereof having elongated slots 33 and 40 parallel to surface 20 and slidably engaged on pins 42 and 44 .xed to a stationary member 46. The supporting member' 36 and head 10 may then be moved rightwardly to the position shown in FIG. 6 by any suitable means, not shown, to deliver the leading edge of sheet S into the nip of forwarding rollers 32 and 34.

As the sheets are separated individually and successively from the stack S, the stack is advanced accordingly to a predetermined feeding level by means of a suitable mechanism E adapted for elevating the table 14.

What is claimed is:

1. A device for separating the end sheet from a stack of sheets comprising, an elongated body having a iirst flat surface and a second flat surface at an angle to the first ilat surface and having a groove in said surfaces extending longitudinally of the body from one end of said second at surface, means for positioning said body with the iirst surface adjacent and substantially parallel to the end sheet of said stack and said second surface at an acute angle to said sheet, and means for optionally applying a stream of high velocity air under vauc-uum or positive pressure longitudinally through a portion of the groove in the first surface to cause said sheet to adhere successively to said first and second tiat surfaces and seal as least a portion of said groove, the air continuing to flow through said groove through said one end after said sealing of said portion of said groove.

2. A pneumatic device for separating the end sheet from a stack of sheets comprising, an elongated body having a iiat side and an elongated groove in said side extending longitudinally of the body from one end thereof, means for supporting said body with its x'iat side adjacent and substantially parallel to the end sheet of said stack, means for advancing the stack towards the body, and

means for optionally introducing a stream of high velocity and seal at least a portion of said groove, the air continuing to ilow through said groove through said one end after said sealing of said portion of said groove.

3. A sheet separator for removing sheets one at a time in succession from a stack of sheets comprising, an elongated body having rst and second flat surfaces at an angle to each other and having a groove in said surfaces extending longitudinally of the body from one end thereof, means for supporting the body with said rst surface adjacent and substantially parallel to the end sheet of said stack and with said second surface at an acute angle to said sheet, means for advancing the stack of sheets toward said body means for optionally applying a stream of high velocity air under vacuum or positive pressure through a portion of the groove in said first surface to separate the top sheet from the stack and cause it to adhere progressively and in succession to said irst and second surfaces, to seal at least a portion of said groove, the air continuing to flow through said groove through said one end of said body after said sealing of said portion of said groove, and means to strip the separated sheet from said surfaces.

4. A mechanism for removing Workpieces individually from a stack comprising, means for supporting a stack of workpieces, an air foil disposed over the stack and having a first portion adjacent to the stack at a point remote from a free edge of the uppermost workpiece of the stack and diverging relatively to the stack toward a second portion disposed substantially over and in spaced relation to the free edge of the workpiece, means for directing a stream of air along said air foil, means for providing and for controlling a supply of air to said directing means, and movable carriage means including a ilat workpiece supporting surface which is dat in the direction of movement of the carriage means, said carriage means being reciprocably movable in translation in a direction substantially parallel to the plane of said workpiece supporting surface and providing a support for conveyance of the workpiece from the stack after the free edge of the workpiece has been raised from the stack by the action of said air foil.

5. An apparatus for removing workpieces individually from a stack comprising, a platform for supporting a stack of workpieces, an air foil disposed in a first position over the stack and having a first portion adjacent to the stack at a point remote from a free edge of the endmost Workpieces of the stack and diverging relatively to the stack toward a second portion disposed near and in spaced relation to the free edge of the workpieces, said air foil being movable in translation to said first position for removing a workpiece from the stack and being reciprocably movable in translation from said first position to a second position for conveying and delivering the Workpiece to subsequent devices, means moving with said air foil for directing a sole stream of air along said air foil in such manner that it cooperates with the air foil for removing a workpiece from the stack and holds the workpiece against the air foil for conveying and delivering the workpiece to said subsequent devices, and means for providing and for controlling a supply of air to said directing means.

6. A mechanism for removing Workpieces individually from a stack comprising, means for supporting a stack of Workpieces, an air foil disposed in a iirst position over the stack and having a first portion adjacent to the stack at a point remote from a free edge of the uppermost workpiece of the stack and diverging relatively to the stack toward a second portion disposed substantially over and in spaced relation to the free edge of the workpiece, said air foil being movable in translation to said first position for removing a workpiece `from the stack, and being reciprocably movable in translation from said rst position to a second position for conveying and delivering the workpiece to subsequent devices, means carried by and moving with said air foil Ifor directing a stream of air along said air foil from said first portion toward said second portion in such manner that it cooperates with the air foil for removing a workpiece from the stack and for conveying and delivering the workpiece to said subsequent devices, means for providing and for controlling a supply of air to said directing means, and carriage means supporting and moving said air foil, said carriage means including a at surface which is flat in the direction of movement of the carriage means for supporting a workpiece being conveyed and delivered by said air foil and being reciprocably movable in translation in a direction substantially parallel to the plane of said fiat surface.

7. A mechanism for removing sheets individually from a stack comprising, means for supporting a stack of sheets, an elongated body disposed over the stack and having a rst portion adjacent to the stack at a point remote from a free edge of the uppermost sheet of the stack and diverging relatively to the stack toward a second portion disposed substantially over and in spaced relation to said free edge of the sheet, said elongated body having an elongated groove common to said rst and second portions and extending longitudinally of the body, means for directing a stream of air longitudinally through a portion of said groove in such manner that it will ow substantially parallel to said end sheet to cause said end sheet to rise from the stack and adhere to said elongated body'and seal at least a portion of said groove, means for providing and for controlling a supply of air to said directing means, and movable carriage means including a at sheet supporting surface which is flat -in the direction of movement of the carriage means, said carriage means being reciprocably movable in translation in a direction substantially parallel -to the plane of said sheet supporting surface and providing a support for conveyance of the sheet from the stack after the sheet has been raised from the stack by the action of said air stream.

References Cited in the ile of this patent UNITED STATES PATENTS 1,418,145 Fischer May 30, 1922 1,495,881 Bunger May 27, 1924 1,635,626 Liljebladh July 12, 1927 2,791,424 Noon May 7, 1957 2,819,075 Noon Ian. 7, 1958 2,819,076 Wendt et al lan. 7, 1958 2,905,466 Azari et al. Sept. 22, 1959 2,953,371 Smith Sept. 20, 1960 

1. A DEVICE FOR SEPARATING THE END SHEET FROM A STACK OF SHEETS COMPRISING, AN ELONGATED BODY HAVING A FIRST FLAT SURFACE AND A SECOND FLAT SURFACE AT AN ANGLE TO THE FIRST FLAT SURFACE AND HAVING A GROOVE IN SAID SURFACES EXTENDING LONGITUDINALLY OF THE BODY FROM ONE END OF SAID SECOND FLAT SURFACE, MEANS FOR POSITIONING SAID BODY WITH THE FIRST SURFACE ADJACENT AND SUBSTANTIALLY PARALLEL TO THE END SHEET OF SAID STACK AND SAID SECOND SURFACE AT AN ACUTE ANGLE TO SAID SHEET, AND MEANS FOR OPTIONALLY APPLYING A STREAM OF HIGH VELOCITY AIR UNDER VAUCUUM OR POSITIVE PRESSURE LONGITUDINALLY THROUGH A PORTION OF THE GROOVE IN THE FIRST SURFACE TO CAUSE SAID SHEET TO ADHERE SUCCESSIVELY TO SAID FIRST AND SECOND FLAT SURFACES AND SEAL AS LEAST A PORTION OF SAID GROOVE, THE AIR CONTINUING TO FLOW THROUGH SAID GROOVE THROUGH SAID ONE END AFTER SAID SEALING OF SAID PORTION OF SAID GROOVE. 